This Core now supports basic, translational and clinical research. The Flow Cytometry and Immune Monitoring Core Facility has been broadened to include an immune monitoring component to provide stateof- the-art technologies for cellular and serum analysis available to Cancer Center investigators with interest in basic science or clinical applications. Since the last submission the Flow Cytometry component has acquired two new state-of-the-art instruments: a dual laser high speed digital cell sorter and a dual laser analyzer. With this instrumentation the Core is able to accommodate the increasing applications that investigators request. The personnel managing this facility have served Cancer Center members for over 20 years. In the last year the Facility was utilized by 32 different Cancer Center members that represent an increase of 60% over the previous grant submission. These investigators accounted for 88% of the Facilities total usage. The new Immune Monitoring component offers services to investigators engaged in clinical immunotherapy trials. These include cancer vaccines or cytokines, or clinical trials in which the immune status of the patient might provide predictive or diagnostic information. An example of the latter is cytokine levels that might be linked to a disease outcome. In addition, this component will also assist preclinical researchers that want to analyze immune responses in animal (tumor) models. The services include the current standard for immune monitoring: the ELISPOT assay for detection of cytokines released by activated T cells, intracellular cytokine staining, enumeration of T cells by tetramer analysis, a multiplex assay for detection of up to 13 cytokines as well as radioisotope-based proliferation and cytotoxicity assays. Another critical service the core provides is the standardized isolation of serum and cells from (apheresed) blood specimens and freezing and storing the cells for later analyses. Both components are evaluated by a common User Committee. The Immune Monitoring facility is being set up with a $1M investment in equipment, maintenance contracts and pilot research projects through the Mabel and Arnold Beckman Foundation. No support for the Immune Monitoring component is requested until year 2 when the Beckman foundation grant expires.